JPH09102111A - Cleaning liquid for magnetic head and magnetic head using the same - Google Patents

Abstract

(57) Abstract: A cleaning liquid for a magnetic head, which is excellent in the cleaning effect of the magnetic head and is soluble in a general-purpose solvent. Further, by applying the cleaning liquid for a magnetic head, a magnetic head in which no stain is attached to the sliding surface with respect to the magnetic recording medium and brown stain does not occur is provided. A cleaning liquid is prepared by dissolving a perfluoropolyether compound having an amino group in a solvent.
The two substituents bonded to the nitrogen atom of the amino group are
It may be hydrogen or hydrocarbon, but if one of them is a long-chain hydrocarbon group having 10 or more carbon atoms, it will be easily dissolved in a general solvent other than the perfluorocarbon-based solvent. On the other hand, the perfluoropolyether group may be monofunctional or polyfunctional. Such a cleaning liquid may be held on the sliding surface of the magnetic head with respect to the magnetic recording medium.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning liquid for a magnetic head used as a cleaner for a magnetic head for recording / reproducing information on / from a magnetic recording medium. The magnetic head.

[0002]

2. Description of the Related Art Generally, in a magnetic recording medium, particularly a magnetic tape, it must be slid at high speed with a magnetic head in the process of recording / reproducing a magnetic signal, and at that time, it must be smoothly and stably run. . However, in the above magnetic recording medium, since the surface of the magnetic layer is smoothed for high density recording, a substantial contact area with the magnetic head is increased, and an adhered matter is attached to the magnetic head. A burn-in phenomenon called brown stain is likely to occur.

When such a phenomenon occurs, the output level is lowered and the durability of both the magnetic recording medium and the magnetic head is deteriorated. To solve this, a lubricant is applied to the magnetic layer of the magnetic recording medium. Is held. For example, in a so-called coating type magnetic recording medium having a magnetic layer containing magnetic powder and a binder as main components, a lubricant may be internally added to the magnetic layer or a lubricant may be coated on the magnetic layer. Being tried. Also in a so-called metal magnetic thin film magnetic recording medium, a lubricant is applied to the magnetic layer together with an anticorrosive agent and the like.

However, when a conventionally widely used lubricant is applied to the surface of the magnetic layer, the friction coefficient is initially reduced to improve the running performance, but this lubricant is gradually used for the magnetic head, the guide pin, etc. There is a problem that the sliding member is scraped off and the effect is reduced. Further, in the coating type magnetic recording medium, even if a lubricant is applied to the surface of the magnetic layer, the lubricant diffuses into the magnetic layer and is exhausted especially after aging. When the lubricant on the surface of the magnetic layer is depleted in this way, the organic substance in the lubricant, and in the case of a coating type magnetic recording medium, the organic substance in the binder easily adheres to the magnetic head again. . further,
The impurities adhering to the magnetic head change into substances that are insoluble in general-purpose solvents, resulting in brown stains.

In order to solve this, before the brown stain is generated on the magnetic head, the magnetic head is regularly cleaned or the above-mentioned dirt is prevented from adhering to the magnetic head. As a cleaning liquid for this purpose, a product such as Deck Solvent manufactured by ING Co., Ltd. is commercially available.

This cleaning liquid contains perfluoropolyether having a polar group as a main component, and by cleaning the sliding surface of the magnetic head with the magnetic recording medium, impurities and magnetic powder adhered to the cleaning liquid are cleaned. Etc. can be removed. In addition, the presence of polar groups makes it possible to prevent the stains from adhering to the metal and making it difficult for dirt to adhere to the magnetic head. Therefore, applying this cleaning liquid to the sliding surface of the magnetic head in advance will prevent the generation of brown stains. can do.

[0007]

However, in the above-mentioned cleaning liquid, since the main component perfluoropolyether does not dissolve in a general-purpose solvent, a perfluorocarbon (C _n F _{2n + 2} ) type solvent is used as the solvent. This has to be done, which makes this cleaning liquid very expensive. In addition to perfluorocarbon solvents, chlorofluorocarbons (so-called CF
Although it can be dissolved in a C-fluorocarbon-based solvent, many of the chlorofluorocarbon-based solvents are said to adversely affect the global environment.

Therefore, the present invention has been proposed in view of the above circumstances, and an object of the present invention is to provide a magnetic head cleaning liquid which is excellent in the effect of cleaning the magnetic head and which can be dissolved in a general-purpose solvent. It is another object of the present invention to provide a magnetic head in which the cleaning liquid for the magnetic head is applied so that the sliding surface with respect to the magnetic recording medium does not become dirty and brown stain does not occur.

[0009]

The cleaning liquid for a magnetic head according to the present invention has been proposed in order to achieve the above-mentioned object, and a perfluoropolyether compound having an amino group is dissolved in a solvent. It will be.

The perfluoropolyether compound having an amino group is represented by the following general formulas (1) and (2).

R ^f1 —CH ₂ NR ¹ R ² (1) NR ³ R ⁴ CH ₂ —R ^f2 —CH ₂ NR ⁵ R ⁶ (2) where R ^f1 and R ^f2 are perfluoro Represents a polyether group, and R ^{1 to} R ⁶ represent hydrogen or a hydrocarbon group.

The two substituents R ¹ and R ² , R ³ and R ⁴ , and R ⁵ and R ^{6 which} are bonded to the nitrogen atom of the amino group have long-chain carbonization of 10 or more carbon atoms. It is preferably a hydrogen group. By having a long-chain hydrocarbon group having 10 or more carbon atoms, it becomes easy to dissolve in a general solvent other than a fluorocarbon-based solvent or a CFC Freon-based solvent. This hydrocarbon group may or may not have a double bond, a branch, a ring, or an aromatic ring. In addition, N, O,
Complex elements such as P and S may be contained.

On the other hand, the monofunctional perfluoropolyether group represented by R ^f1 has the following structural formula (3):
^{Examples of the} polyfunctional perfluoropolyether group represented by R ^f2 include those represented by (4) and (5).
Examples include those represented by the following structural formula (6), but the invention is not limited thereto.

F (CF ₂ CF ₂ CF ₂ O) _k ... (3) CF ₃ [OCF (CF ₃ ) CF ₂ ] _l (OCF ₂ ) _m ... (4) F [CF (CF ₃ ) CF ₂ O] _n ... (5) (OCF ₂ CF ₂ ) _p (OCF ₂ ) _q (6) Here, k, l, m, n, p and q are all integers of 1 or more. And has a molecular weight of 6 as perfluoropolyether
The range may be from 00 to 5000. If the molecular weight is too small, the cleaning effect deteriorates, and conversely, if the molecular weight is too large, the effect of the terminal group bonded to this relatively deteriorates. Further, when the perfluoropolyether is represented by the structural formula (6), the ratio of p and q is preferably about 0.5 to 2.0.

When it is desired to reduce the surface energy to suppress the adhesion of dusts and the like, R ^f1 and R ^f2 may be partially fluorinated hydrocarbon groups or perfluorocarbon groups instead of perfluoropolyether groups. . However, in order to suppress the change of the cleaning effect with time, it is preferable that R ^f1 and R ^f2 are perfluoropolyether groups.

The perfluoropolyether compound having such an amino group can be synthesized as follows.
For example, in order to synthesize a perfluoropolyether compound in which R ¹ and R ^{2 in} the general formula (1) and R ³ , R ⁴ , R ⁵ and R ⁶ in the general formula (2) are all hydrogen, The carboxylic acid amide at the end of the fluoropolyether may be reduced using lithium aluminum hydride as a reducing agent. Further, in order to synthesize a perfluoropolyether compound having a long chain hydrocarbon as R ^{1 to} R ⁶ , perfluoropolyether having a carboxyl group is converted to an acid chloride with thionyl chloride and then reacted with a long chain amine. Then, the compound is converted to an amide and then reduced in the same manner as described above. In addition, in order to purify the obtained product, short column chromatography using basic alumina may be performed.

The above-mentioned perfluoropolyether compound having an amino group may be dissolved in a perfluorocarbon type solvent, but may also be dissolved in various general-purpose solvents. Specifically, a hydrocarbon solvent represented by toluene or hexane, a ketone solvent represented by acetone, methyl ethyl ketone, cyclohexanone, or an alcohol solvent represented by ethanol or isopropanol is preferably used. Of course, these may be appropriately mixed and used. However, it is desirable to select a solvent having a boiling point of 50 ° C. or higher so that it can withstand friction when sliding on the magnetic recording medium.

The cleaning liquid prepared by dissolving the above-mentioned perfluoropolyether compound having an amino group in a solvent has a large water repellency and has an excellent effect of reducing the surface energy. Therefore, when this cleaning liquid is applied to the sliding surface of the magnetic head with respect to the magnetic recording medium, it becomes difficult for dirt to adhere to the sliding surface. Therefore, it is possible to prevent the stain from being oxidized and becoming brown stain. As a result, the durability of the magnetic head and the magnetic recording medium can be improved and the output level can be prevented from being lowered. Further, since the cleaning liquid of the present invention has a polar group, it is strongly fixed to the magnetic head and the cleaning effect is not impaired even under severe conditions such as low temperature.

The method for holding the cleaning liquid for the magnetic head on the magnetic head is not particularly limited. For example, the magnetic head may be manufactured by a usual method and then applied by a dipping method. Further, when the user cleans the magnetic head, the magnetic head may be applied again with a cotton swab or the like.

The thickness of the magnetic head cleaning liquid applied to the magnetic head is preferably 0.3 nm to 10 nm, more preferably 0.5 nm to 5 nm. If this coating thickness is too thin, it cannot be held in the magnetic head for a long time. Conversely, if it is too thick, the spacing increases and sticking with the magnetic recording medium occurs. The problem arises.

As a magnetic head to which the present invention is applied,
It may have any configuration, especially when recording / reproducing or when starting / stopping the recording / reproducing operation.
A magnetic head that slides on a magnetic recording medium is suitable. Specifically, general ferrite heads, metal
An in-gap (MIG) type head, a laminated type head, an inductive head, a magnetoresistive effect (MR) type head, etc. are mentioned. Any conventionally known material can be used as the material of these magnetic heads.

Writing / writing is performed by this magnetic head.
As the magnetic recording medium for reading, any of those conventionally applied to each magnetic head can be used, and there is no limitation. Therefore, the structure of the magnetic layer may be a coating type mainly composed of magnetic powder and a binder, or a metal magnetic thin film type. Further, the shape thereof is not limited at all, and may be any conventionally known shape such as a tape shape, a disk shape, and a drum shape.

The magnetic layer in such a magnetic recording medium also holds the magnetic head cleaning liquid held in the magnetic head to exert a lubricating effect, and the magnetic head cleaning liquid is constantly applied to the magnetic head. You may be able to supply.

[0024]

EXAMPLES Hereinafter, specific examples of the present invention will be described, but it goes without saying that the present invention is not limited to these examples.

Example 1 In this example, a cleaning liquid was prepared using a compound having amino groups at both ends of a polyfunctional perfluoropolyether.

Specifically, the structure of the perfluoropolyether group represented by R ^f2 in the above-mentioned general formula (2) is CF ₂ (OCF ₂ CF ₂ ) _p (OCF ₂ ) _q OCF ₂
And the molecular weight of the perfluoropolyether group is 20
And a structure in which R ³ , R ⁴ and R ⁵ , R ⁶ in the amino group are C ₁₈ H ₃₇ (hereinafter referred to as compound 1) is dissolved in ethanol to prepare a cleaning liquid. did.

On the other hand, in the magnetic head for holding the cleaning liquid, as shown in FIG. 1, a pair of magnetic core halves 1 and 2 are formed of ferromagnetic oxide, for example, single crystal ferrite. On the ferromagnetic metal thin film formation surface where the joint surfaces of the bodies 1 and 2 are notched diagonally, continuously from the front gap formation surface to the back gap formation surface,
Saturation magnetic flux density B of FeAlSi alloy (Sendust), etc.
The ferromagnetic metal thin film 3 having a high s is adhered and formed. The pair of magnetic core halves 1 and 2 is made of SiO.
The abutting surfaces of the ferromagnetic metal thin film 3 are abutted with each other via a gap material such as ₂ and form a magnetic gap. The non-magnetic material 4, in the groove in which the ferromagnetic metal thin film 3 is formed,
The non-magnetic material 5 is filled in the cut grooves for restricting the track width, and the abutting surfaces of the magnetic core halves 1 and 2 restrict the depth of the magnetic gap g and the coil 8 is wound. Winding grooves 6 and 7 are formed.

Then, the above-mentioned cleaning liquid was applied at a coating thickness of 0.5 to 5 nm on the sliding surface 9 with the magnetic recording medium in the magnetic head having such a structure.
This magnetic head is the magnetic head of the first embodiment.

Examples 2 to 7 In this example, a compound having a molecular weight of R ^f2 in the general formula (2) and a structure of R ³ , R ⁴ and R ⁵ , R ⁶ different from the compound 1 was used.

Concretely, except that compounds having the molecular weight of R ^f2 and the structures of R ³ , R ⁴ and R ⁵ , R ⁶ shown in Table 1 (Compound 2 to Compound 7) were used, A cleaning liquid was prepared in the same manner as in 1.

[0031]

[Table 1]

Then, the cleaning liquid as described above is applied to the magnetic head in the same manner as in Example 1, and then the second to seventh examples are applied.
I got a magnetic head.

Examples 8 to 14 In this example, a compound having an amino group at the terminal of a monofunctional perfluoropolyether was used.

Concretely, except that compounds (compounds 8 to 14) whose structures and molecular weights of R ^f1 and R ¹ and R ^{2 in} the general formula (1) are shown in Table 1 were used, were used. A cleaning liquid was prepared in the same manner as in Example 1. However, only compound 14 was dissolved using perfluorooctane as a solvent.

Then, the cleaning liquid as described above was applied to the magnetic head in the same manner as in Example 1, and then the Examples 8 to 1 were used.
4 magnetic heads were obtained.

Examples 15 to 20 In this example, different solvents were used to dissolve the above compounds.

Specifically, the above compound 1 was dissolved in each of isopropanol and methyl ethyl ketone instead of ethanol to prepare a cleaning liquid, which was applied to each magnetic head in the same manner as in Example 1, The magnetic heads of Example 15 and 15 were obtained.

Further, the above-mentioned compound 4 was dissolved in isopropanol, methyl ethyl ketone, toluene and hexane instead of ethanol to prepare a cleaning liquid, which was applied to each magnetic head in the same manner as in Example 1, 17, Example 18, Example 19, Example 20
I got a magnetic head.

The combinations of the compound and the solvent contained in the cleaning liquid applied to the magnetic heads of Examples 15 to 20 are as shown in Table 2.

[0040]

[Table 2]

Comparative Examples 1 and 2 For comparison, here, instead of compounds 1 to 14, perfluoropolyether compounds having terminal carboxyl groups, perfluoropolyether having terminal carboxyl groups and alcohols. The ester compound of and was used.

Specifically, HOCOCF ₂ (OCF ₂ C
A cleaning liquid was prepared by dissolving a perfluoropolyether compound of F ₂ ) _p (OCF ₂ ) _q OCF ₂ COOH in perfluorohexane, and the cleaning liquid was applied to a magnetic head in the same manner as in Example 1 to obtain a comparative example. A magnetic head of No. 1 was obtained.

Further, CH ₃ OCOCF ₂ (OCF ₂ CF
₂ ) _p (OCF ₂ ) _q OCF ₂ COOCH ₃ An ester compound of perfluoropolyether is dissolved in perfluorooctane to prepare a cleaning liquid, which is applied to a magnetic head in the same manner as in Example 1. A magnetic head of Comparative Example 1 was obtained.

Comparative Example 3 In this comparative example, none of the above-mentioned cleaning liquids was used.

That is, a magnetic head having the same structure as in Example 1 was prepared except that the cleaning liquid was not applied, and this was used as the magnetic head of Comparative Example 3.

Evaluation of Characteristics Here, the magnetic head was actually reproduced using the magnetic heads shown in Examples 1 to 20 and Comparative Examples 1 to 3,
The contamination of each magnetic head and the error rate associated with the level reduction were examined.

To prepare a magnetic tape used for measurement,
First, the following materials were prepared.

Ferromagnetic metal powder 100 parts by weight Vinyl chloride-vinyl acetate copolymer 10.5 parts by weight Polyurethane resin 10.5 parts by weight Carbon (antistatic agent) 5 parts by weight Methyl ethyl ketone 150 parts by weight Toluene 150 parts by weight Cyclohexanone 100 parts by weight Parts 2 parts by weight of stearic acid butyl ester These materials were mixed in a ball mill for 24 hours, taken out through a filter, and then 4 parts by weight of a curing agent (Coronate L manufactured by Japan Polyuretan) was added and further 3 parts
A magnetic coating material was obtained by stirring for 0 minutes.

Next, the magnetic paint was applied onto a polyethylene terephthalate film having a thickness of 8 μm and the thickness after drying was 3 μm.
After being coated so as to have a thickness of m, it was oriented in a magnetic field, dried, wound, calendered, and cut into 1/2 inch width to complete a magnetic tape.

Then, in an atmosphere of 25 ° C. and 60% RH or in an atmosphere of 40 ° C. and 80% RH, the magnetic heads shown in Examples 1 to 20 and Comparative Examples 1 to 3 were respectively mounted on the drives to perform the above-mentioned operations. After writing / reading data to / from 32000 blocks of the magnetic tape having such a configuration was repeated for 4 hours, the contamination of each magnetic head and the error rate due to the level down were examined.

The magnetic head is evaluated as ◯ if the surface of the ferromagnetic metal thin film 3 near the front gap is not dirty, Δ if it is slightly dirty, and × if more than half is oxidized and causes brown stain. evaluated. Although quantitative evaluation is difficult, if the area of the stain adhered to the surface of the ferromagnetic metal thin film 3 is within 20%, it is evaluated as ◯.

As the error rate, the ratio of blocks in which normal writing / reading could not be performed was measured.

The measurement results of the magnetic heads of Examples 1 to 7 are shown in Table 3, the measurement results of the magnetic heads of Examples 8 to 14 are shown in Table 4, the measurement results of Comparative Examples 1 to 3 are shown in Table 5, and Example 15 is given. Table 6 shows the measurement results for each sample.

[0054]

[Table 3]

[0055]

[Table 4]

[0056]

[Table 5]

[0057]

[Table 6]

From the above results, in the magnetic heads of Examples 1 to 20 shown in Tables 3, 4 and 6, the brown stain did not occur and the error rate could be suppressed to a small level. It can be seen that in the magnetic heads of Comparative Examples 1 to 3 shown in 1), dirt adheres and the error rate increases.

From this, it can be seen that the application of the cleaning liquid makes it difficult for dirt to adhere to the sliding surface of the magnetic head with respect to the magnetic recording medium. In addition, the compounds 1 to 14 (perfluoropolyether compounds having an amino group) used in Examples 1 to 14 show an excellent cleaning effect than the compounds used in Comparative Examples 1 and 2. I understand. It was also found that the perfluoropolyether compound having an amino group exhibits an excellent cleaning effect regardless of the type of solvent in which it is dissolved.

[0060]

As is clear from the above description, the magnetic head cleaning liquid according to the present invention exhibits an excellent cleaning effect for a long time even under severe operating conditions. Moreover, various hydrocarbon solvents can be used as the solvent, and fluorocarbon or chlorofluorocarbon solvents are not required.

Therefore, when this is applied to the sliding surface of the magnetic head with respect to the magnetic recording medium, it is possible to prevent the stain from adhering to the sliding surface and prevent the occurrence of brown stain. As a result, the durability of the magnetic head and the magnetic recording medium can be improved and the output level can be prevented from being lowered.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration example of a magnetic head to which the present invention is applied.

[Explanation of symbols]

 1, 2 Magnetic core half body 3 Ferromagnetic metal thin film 4, 5 Non-magnetic material 6, 7 Winding groove 8 Coil 9 Sliding surface

Claims (3)

[Claims] 1. A magnetic head cleaning liquid obtained by dissolving a perfluoropolyether compound having an amino group in a solvent. 2. A perfluoropolyether compound having an amino group is represented by the following general formula (1) or general formula (2):
The cleaning liquid for a magnetic head according to claim 1, which is represented by R ^f1- CH ₂ NR ¹ R ² ... (1) NR ³ R ⁴ CH ₂ —R ^f2- CH ₂ NR ⁵ R ⁶ ... (2) where R ^f1 and R ^f2 are perfluoropolyether groups. And R ^{1 to} R ⁶ represent hydrogen or a hydrocarbon group. 3. A magnetic head characterized in that a cleaning liquid for a magnetic head obtained by dissolving a perfluoropolyether compound having an amino group in a solvent is held on a sliding surface with respect to a magnetic recording medium.